Even out in broad daylight he still its on top of the filter, he only seems active at night when i put the light on him, but last night he didnt cause it was prolly the water change.

He's been like this since i got him, hardly ever moves around the tank even when i moved the filter/heater around. Mum ordered him in from the shop so he wasnt there for long so i cant ask what food they use cause they prolly didnt get a chance to feed him

Aww. All I can suggest is keeping up with your water changes, maybe change around some decor and try it with and without the air stone. Maybe he's just still adjusting. Are you planning to cycle? I dunno if you can cycle 3 gallons - might be a challenge to keep up with it. You'd have to watch the parameters constantly.

If not cycling, I'd change the water twice a week - once 50%, once 100% (not sure if this is what you're doing already!).
If you're going to try to cycle, perhaps hold off until he starts to feel more comfortable so the water is ultra clean for him until then.

I hope he starts being more active! Based on your other thread, he can't possibly be cold. What a finicky boy.

Yeah i guess he's stressed cause i was forced to do a cycle with him in the tank. and i did a 50% water change yesterday and watching the levels religiously, bought a NO3 and KH testers today, Nitrite level has gone down since a few days ago but Ammonia may have gone up a little bit.

When doing a 100% water change do i clean out all the left over food thats settled on the bottom? and how can i heat up the new water and keep him warm when i only got one heater?

Interesting that you have nitrite already. Maybe you shouldn't do any 100% changes, as it seems like the tank is already starting to cycle. Just keep up with frequent (daily or every other day) 50% changes. If you don't want to cycle the tank yet, then just do 100% changes like I said before.

Either way, you want to remove the leftover food and such from the bottom. You can either use a turkey baster or a siphon. If you want to siphon, get a bubbler tube (air stone tube) and a bucket. Put one end of the tube in the tank, and suck in on the other end until you see the water get up over the tank edge. Throw the other end into the bucket and you should get water drainage. This will also make doing 50% changes easier for you.

To get water of the same temperature to put back in the tank, just match your tap water temperature by using part hot water, part cold water. You can take a cup of the fish tank water and put it by the sink so you can match the temperature. Make sure you use your water conditioner! If you're using spring water (I think you said that earlier), just add some hot tap water to it. You should condition spring water anyway, because many times it's treated.

Yeah i even get my mum to double check the testers =/ dont use water straight out of the tap, but i use Puratap, and being a 12 liter tank (roughly 3 gallon) the conditioner directions say use 4ml for every liter of water, its only a 60ml bottle and thats a bit much for my tank right?

fish almost always eat anything if they get hungry enough. My uncle bred bettas and when i got my first fish from him. all it would eat would be bloodworms. then we tried a flakes or no food and he came around.

Wow, that's some super-diluted water conditioner! A lot of people here suggest Prime because of how little you have to use (like two drops per five gallons or something ridiculous like that). I use Amquel (5 mL per 10 gallons), which is also more concentrated. Going to switch to Prime when I run out, though.

Sometimes fish just get sad... it seems like everything else in the tank is perfect! I wonder if he's just depressed for some reason. Or maybe bored?